The objective of this proposal is to examine the effect of a novel interoperable ?internet intervention? for patients with Obstructive Sleep Apnea syndrome (OSA) that integrates a telemetry treatment device and an internet-based portal that facilitates patient-centered, collaborative management for patients prescribed the gold-standard treatment, continuous positive airway pressure (CPAP). Poor treatment adherence with CPAP therapy is well-documented. Set against a backdrop of telemedicine applications that have grown as fast in unsubstantiated claims and assumptions of patient satisfaction, diagnostic accuracy, clinical efficacy, and cost-effectiveness as they have in technological sophistication and capabilities, the evaluative aspect of this proposal is designed as a randomized, controlled clinical trial?Usual Care patients (control) versus i-PAP patients (intervention). An important empirical-methodological advantage of the project is the objective measurement of CPAP adherence, which is measured by internal microprocessor as the ?amount of time CPAP is used at the prescribed pressure.? This objective measurement allows feedback of treatment adherence and efficacy to both patient and provider, and we have designed the i-PAP intervention around this central feature. Because it is well-known that adherence patterns are established very early in treatment, i-PAP is designed to provide new CPAP users with education and support they require to get started on CPAP: The Learning Center provides education about OSA and CPAP;the interactive Troubleshooting Guide helps the patients troubleshoot and solve CPAP problems;My Charts allows graphical representation not only of treatment adherence data, but treatment efficacy data as well;My Journal allows the journaling of the patient?s experiences;My Assessments allow the patients to enter their own data and track their progress on a number of measures;My Message Board facilitates timely interactions with sleep providers (and in the future other OSA patients). Essentially, i-PAP is designed to provide the care that patients want and need, at the time they want and need it. The overarching aim of the present project is to examine the effect of this patientcentered, collaborative care ?internet intervention? on increasing CPAP adherence to a clinically meaningful level and to examine the potential mediators of this effect. The central questions that encompass the conceptual and empirical contours of the study: Does the i-PAP intervention have an effect on the patient?s experience of care, CPAP adherence, and OSA outcomes relative to usual care, and if so, what are the possible mechanisms that account for the effect?